Process for the preparation of chlorhydrins



Dec. 28, 1937. P. FERREROYET AL 2,103,813

PROCESS FOR THE ELREP ARATION OF CHLORHYDRINS Filed April 5, 1936 clerk/ ya Pissed n... 28, 1931 r 2,103,813

UNITED STATES PATENT OFFICE rnocriss Fgg gggl figwfloli or bochimique,- Socit Anonyine, Brussels, Belgium, a Belgian company Application April s, 1930, Serial no. 12,640

In France April 15, 1935 3 Claims. (Cl. 260-157) The present/invention relates to a process perdifficulty, not to speak of the large expenditure mitting of preparing in a continuous manner of energy to be contemplated. chlorhydrins directly from water, chlorine and The operative conditions can be improved by oleflnes, either diluted or not, and of obtaining introducing the chlorine and the oleflne separate- -5 a maximum yield in a rational apparatus with 1y, for example by recirculating the solution in 5 a very small expenditure'of energy. a closed circuit, and successively introducing the It is known that in 'order to prepare chlortwo gases by separate devices, which-process may hydrins such as ethyle'nic chlorhydrin, propylenic be made continuous. In this case also, the nechlorhydrin etc., it suflices to add a molecule of cesslty of avoiding the presence of free chlorine hypochlorous acid to a molecule of the corregas and its contact with oleflne in the gaseous sponding olefine, this reaction taking place in phase, makes it necessary to operate with very aqueous solution. The requisite hypochlorous dilute solutions, and under such conditions that acid may be obtained in different ways. It may all the chlorine be hydrolized before it enters be freed from .hypochlorites by the action of carthe reaction chamber.

bonic acid, or chlorine may be introduced into It has also been pr p s d to reeirculate the 15 an alkaline solution. In some processes for the solution through two towers in series, said to ers continuous production of chlorhydrins comprlsbeing eonst d s mbbe s""tfi"fi i s m ing the separate introduction of chlorine and terial. The liquid flowing down in thefirst tower olefine hydrocarbon in the solution, it has been meets an ascending stream chlorine. h

proposed to carry out the reaction in the prescharged with chlorine, it crosses the second tower 20 ence of an alkali or of a salt adapted to react which receives an ascending stream of olefinei with the hydrochloric acid formed, thus avoiding This, in fact, amounts to a liquid dispersion in the presence in the solution of any free chlorine. gaseous phas but this manner of p e di s In carrying out these processes use has been disadvantageous, inasmuch as it does not makemade of apparatus in which the step of preit possible to avoid in the second tower a partial 25 paring the hypochlorous acid was effected in a degassing of the chlorine in this gaseous phase smaller volume than the step of preparing the and consequently to avoid undue formation of 'chlorhydrin, whereby the degree of concentrah logenated derivates, P l y when diluted tion of theflnal product was favourably affected. efin are Operated With- However the presence of alkalis or salts is detri- In order to avoid operating two scrubbers of 30 mental to the reaction and one half of the chloarg s z and t av d th d r m ta as us rine is lost in the form of-alkall metal or alkaline phase. wh e n vert el s preserving e P nc earth metal chloride of no practical value. ple of the successive introduction of the two gas- It is also known to introduce chlorineand the 80118 r e t in ac cuit t u h wh ch he olefine into the solution without the use of a solution flows, it has also been proposed to 'opneutralizing agent, to produce the two successive smile i an Ordinary PIP In Such P p the reactions: chlorchydrin solution .is actively recirculated un- C12+H20=010H+H01 der pressure, the chlorine-being broughtat a 0H predetermined point and the olefine at'a further 40 point, under such conditions that the reaction 40 oion+c.m ..=o..m. is terminated before the liquid reaches a recep- 01 I tacle from which it is recirculated. In order to obtain with such process an hourly production In thi case, h w r the low Solubility of the acceptable on an industrial scale, as the reaction r act s s. par c arly o the l fl e. in Water is limited by its own speed which is function or and the neces ity o op a with dilute chlethe dispersion of the olefine, one has to recircu rine solutions, necessitate the use or very larg late at a very high rate a large volume giving volumes; it is also necessary to resort to powerrise to a large expenditure of ener y, and be ful mechanical means, in. order to ensure a good isfied with a relatively small production of chlorodispersion of the gases, so as to limit as much as hydrin per cycle. t 50 possible a direct addition of chlorine to the olefine The object of our present invention is to proin the gaseous phase,-which would lead to the vide a process i'or the production of chlorohydrin production of undesirable halogenated derivates from chlorine, water and olefines, in a simple in undue proportions. The use of special antimanner and with very high yields,'without how- 5; acid materials which have to be resorted to, is 2. ever using any salts or agents adapted to neutralof at least 15% ize the hydrochloric acid formed, so that in addition to the above mentioned advantages we obtain the chlorhydrin in a hydrochloric solution be separated in the manner set forth in our co-pending application Ser. No.

55,926 filed December 23, 1935,'whereby the hy-e. converted into a valuable bydrochloric acid is product. This invention is based upon the observation that contrary to what was generally admitted, it is possible to work with concentrated solutions of chlorine, i. e. with chlorine solutions of saturation or more, without neutralizing agents, provided no discontinuity in the liquid phase is allowed to take place in the circulating system.

Our invention therefore comprises a cont'nuous process of preparing chlorhydrins' from chlorine, water and olefine by recirculating the solution and carrying out the step of forming hypochlorous acid and the step of forming the chlorohydrin in volunies of solution respectively adapted to the degree of solubility of the reacting gases, said process being characterized in that the circulation is so controlled that a chlorine solution of saturation is formed in the absence of any neutralizing agent, and said solution is caused to react with the olefine there being no discontinuity in the liquid phase during the circulation. ed claims we refer to a chlorine concentration of at least 15% of saturation, this is to be understood as applied to a solution at ordinary temperature (20 C.).

In carrying out the process, use is made of a tubular side circuit, branched on the reaction chambeigdn which .side circuit the dissolving of the chlorine is effected so as to avoid any discontinuity in the liquid phase and so as to lead to the formation of a chlorine solution of at least 15% of saturation. The chlorhydrin concentration is kept at the desired value by feeding the circuit with fresh water, in amounts .proportioned to the withdrawal of the solution.

Under these conditions we may use olefine either in the pure state or diluted and it is not necessary either to use expensive gas diffusing means, or to resort to over-pressure, or to an excess of olefine. Our improved process ensures a high hourly output, and permits of a. remunerative recuperation of the hydrochloric acid formed.

The accompanying diagrammatic drawing illustrates a constructional form of the apparatus.

The reaction is carried out in a tower l. of material which is resistant to hydrochloric acid and chlorine; the dispersion of olefine is assured, for example, by means of a plate 2 of porous material, but it is understood that any other suitable means might be used to that end. The tower is filled with solution up to the level A- -B. The solution is sucked from the top of the tower and forced into the bottom thereof by means of a small recirculation pump 4, inserted in a branch circuit 3 in which the chlorine solution is'prepared. The chlorine is introduced at 5 immediately beforethe pump. The olefine, or the gas containing the same,'is introduced at 6 at the bottom of the tower, the inert gases escape at I towards the apparatus for subsequently utilizing same. When the required chlorhydrin concentration is reached, the system is fed with a suitable amount of fresh water at 8 and an equiva lent amount of solution is withdrawn at 9.

It is also possible to operate with a reverse circulation of the liquid so that same will flow When herein and in the append-v through the tower line, the branch circuit being suitably modified in contracurrent to the oleand any discontinuity in the liquid phase still being avoided; experience shows however that preference is to be given to parallel circulation.

'I'he'reaction maybe applied to'olefine of the ethylene and propylene type or to their mixture, whether or not in presence of inert substances. Two non-limitating examples of applying the invention to ethylene and carrying out the process in this particular case, will now be given:

Example 1 The apparatus is fed at the rate of 10m /h. of ethylene at 40% and 3,9m /h. of chlorine, the rate of recirculating the liquid being regulated so as to produce a chlorine solution at 20% of saturation at 20 C. The introduction of fresh water and the tapping of the solution are carried out so as to keep the percentage of chlorhydrin at about 4%. The temperature is kept at 20 C. The yield in ethylenic chlorhydrin reaches 90% and in dichlorethane 8% with respect to the ethylene consumed. Practically no chlorine is found in. the residual gases.

We claim:

1. In a continuous process-of preparing chlorhydrin from chlorine, water and olefine, causing water to react with chlorine at a comparatively high rate of speed to form a solution of hypochlorous acid and of hydrochloric acid, causing said solution to react with an olefine at a comparatively low rate of speed, circulating the solu tion in a closed circuit while avoiding any discirculation in manner that a chlorine solution of at least of saturation is formed in the absence of any neutralizing agent, before it is brought into contact with the olefine.

2. In a continuous process of preparing chlorhydrin from chlorine, water and olefine, causing water to react with chlorine in a limited space to form a solution of hypochlorous acid and of hydrochloric acid, causing said acid solution to react with olefine in a larger space, circulating the solution in a closed circuit from said limited space to said larger space and back to said limited space, and controlling the circulation in such manner that a chlorine solution of at least 15% of saturation is formed in the absence of any neutralizing agent, before it is brought into contact with the olefine,

3. In a continuous process of preparing chlorhydrin from chlorine, water and olefine, causing water to react with chlorine in a limited space vspace to said larger space and back to said lim- The temform a solution of hypochlorous acid and of p ited space, withdrawing solution from and introis formed in the absence of any neutralizing agent ducing water into the solution onits way from before said solution is caused to react with the said larger space to said limited space, and conoleiflne. trolling the circulation of the solution and the PAUL FERRERO.

5 introduction of water in such manner that a CORNEIILE VANDENDRIES. 5

chlorine solution of at least 15% of saturation 

